1. Field of the Invention
The present invention relates to an unequal error encoding and modulation scheme and apparatus for transmitting uncompressed video signals in a wide-band and high-frequency wireless system. More particularly, the present invention relates to an unequal error encoding and modulation scheme and apparatus for transmitting uncompressed video signals in a wide-band and high-frequency wireless system, which is capable of maintaining a possible high-speed transmission/reception rate and also transmitting and receiving a variety of uncompressed video signals robust against radio channel bit errors.
2. Description of the Related Art
The degree of importance of video information bits in video information differs unlike typical data information in which all information bits have the same degree of importance. For example, high-order bits of pixel bytes displaying video are more important than low-order bits thereof, and luminance information bits of video are more important than chrominance information bits thereof. Furthermore, in an RGB color system consisting of a red component, a green component, and a blue component, the green component is more important than the red and blue components.
In general, the amount of video information is much greater than that of typical data information. Furthermore, video information must be transmitted at high speed because of a real-time property requirement in information transmission. Also, a radio channel is likely to experience bit errors resulting from various factors, thereby leading to deformation in transmitted information. In order to minimize such information deformation resulting from the bit errors of the radio channel, a transmission terminal may add supplementary information (hereinafter referred to as a ‘channel error correction symbol’) to information to be transmitted, and a reception terminal may recover pieces of deformed information using the channel error correction symbol. However, the channel error correction symbol information is disadvantageous in that it lowers the transmission rate of a channel.
With the importance of video information and a radio channel property taken into consideration, recently developed high-speed transmission wireless systems using an ultra wide-band and high-frequency band are adopting a scheme for distinguishing high-order bits and low-order bits of pixel information bytes constituting video information and adding more channel error correction symbol information to the high-order bits and less channel error correction symbol information to the low-order bits in order to prevent further deformation of important information and improve picture quality. A method of using an unequal error correction scheme according to the importance of signals as described above is called an Unequal Error Protection (hereinafter referred to as a ‘UEP’) scheme.
In a conventional UEP scheme, however, whether bits are important bits is determined based on fixed bit positions. Accordingly, this scheme may not be used when the positions of important bits are dynamically changed.